Dendrocollybia racemosa

(Pers. : Fr.) Petersen & Redhead

a fungus

G4Apparently Secure Found in 23 roadless areas NatureServe Explorer →
G4Apparently SecureGlobal Rank
MediumThreat Impact
Identity
Unique IDELEMENT_GLOBAL.57.9940
Element CodeNFSM000035
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryFungus
Endemicoccurs (regularly, as a native taxon) in multiple nations
KingdomFungi
PhylumBasidiomycota
ClassBasidiomycetes
OrderAgaricales
FamilyTricholomataceae
GenusDendrocollybia
Synonyms
Collybia racemosa(Pers.) Quel.
Concept Reference
Castellano, M.A., E. Cazares, B. Fondrick, and T. Dreisbach. 2003. Handbook to additional fungal species of Special Concern in the Northwest Forest Plan. Gen. Tech. Rep. PNW-GTR-572. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 144 pp. Online. Available: https://www.fs.usda.gov/pnw/pubs/pnw_gtr572.pdf
Taxonomic Comments
The synonyms of Dendrocollybia racemosa include Agaricus racemosus Pers., Collybia racemosa (Pers.) Quél., Microcollybia racemosa (Pers.) Lennox, Mycena racemosa (Pers.) Gray, Sclerostilbum septentrionale Povah, Sclerotium fungorum var. lacunosum (Pers.) Fr., Sclerotium lacunosum Pers., and Tilachlidiopsis racemosa Keissl (Siegel et al. 2019). The populations in Europe, Eastern North America, and northwestern North America are widely disjunct, and may represent different, but undescribed species (Santa Cruz Mycoflora Project 2022).
Conservation Status
Rank Method Rank calculation - Biotics v2
Review Date2022-07-22
Change Date2022-07-22
Edition Date2022-07-22
Edition AuthorsLorelei L. Norvell (2002), rev. C. Nordman (2022).
Threat ImpactMedium
Range Extent>2,500,000 square km (greater than 1,000,000 square miles)
Number of Occurrences81 - 300
Rank Reasons
Dendrocollybia racemosa has a large range, including northwestern North America and Western Europe. It is rare outside the Pacific Northwest of the United States and Canada, but is known from 250 locations, and occurs on many National Forests, State Parks, and National Parks. It is considered common in the Coast Range of northern California. The California Rare Fungi Working Group believes this fungus is common and should be delisted.
Range Extent Comments
Dendrocollybia racemosa has a large range (about 21 million square kilometers) in the northern hemisphere (including Eastern North America, and Western Europe), but it is rare outside the Pacific Northwest of the United States, and British Columbia, Canada (Bazzicalupo et al. 2022, Castellano et al. 2003, Desjardin 1998, iNaturalist 2022, MyCoPortal 2022). It is common and widespread in the California coastal province, and occasional in the foothills of the Sierra Nevada, it has also been documented in Oregon, and Washington, throughout the range of the northern spotted owl (ISMS-ONH 2002, Siegel et al. 2019).
Occurrences Comments
Dendrocollybia racemosa is common and widespread in the California coastal province, and in the Klamath Mountains. In the Sierra Nevada, Dendrocollybia racemosa is found occasionally in the foothills, mainly below 1200 meters elevation. It is known from at least 45 locations in California (Siegel et al. 2019). There may be about 250, or more occurrences (iNaturalist 2022, MyCoPortal 2022).
Threat Impact Comments
Collection data are too sparse and occurrences too spotty and rare to predict what threats will imperil Dendrocollybia racemosa. Presumably whatever threatens the host fungi, general habitat, microclimates, and/or host's substrate or symbiotic partner will likewise imperil Dendrocollybia racemosa. Other threats include incidental catastrophic events (wildfires), road construction, development, and heavy logging activities (Norvell pers comm 2002).
Ecology & Habitat

Habitat

Occurs in mixed hardwood-conifer forests, usually clustered on the remains of rotting mushrooms, particularly those of Lactarius and Russula species (Desjardin et al. 2014, Siegel et al. 2019). One host mushroom species is Russula crassotunicata (Machnicki et al. 2006).
Terrestrial Habitats
Forest/WoodlandForest - Mixed
Other Nations (2)
United StatesN4
ProvinceRankNative
WashingtonSNRYes
New HampshireSNRYes
AlaskaSNRYes
ColoradoSNRYes
OregonS2Yes
MichiganSNRYes
IdahoSNRYes
CanadaN3
ProvinceRankNative
OntarioSNRYes
British ColumbiaS3Yes
Threat Assessments
ThreatScopeSeverityTiming
1 - Residential & commercial developmentSmall (1-10%)Serious or 31-70% pop. declineHigh (continuing)
1.3 - Tourism & recreation areasSmall (1-10%)Serious or 31-70% pop. declineHigh (continuing)
4 - Transportation & service corridorsSmall (1-10%)Serious or 31-70% pop. declineHigh (continuing)
4.1 - Roads & railroadsSmall (1-10%)Serious or 31-70% pop. declineHigh (continuing)
5 - Biological resource useRestricted (11-30%)Moderate or 11-30% pop. declineHigh (continuing)
5.3 - Logging & wood harvestingRestricted (11-30%)Moderate or 11-30% pop. declineHigh (continuing)
7 - Natural system modificationsRestricted (11-30%)Moderate or 11-30% pop. declineHigh (continuing)
7.1 - Fire & fire suppressionRestricted (11-30%)Moderate or 11-30% pop. declineHigh (continuing)
7.1.1 - Increase in fire frequency/intensityRestricted (11-30%)Moderate or 11-30% pop. declineHigh (continuing)

Plant Characteristics
DurationEPHEMERAL FRUITING BODY
Economic Value (Genus)No
Roadless Areas (23)
Alaska (2)
AreaForestAcres
RatzTongass National Forest5,325
Thorne RiverTongass National Forest72,983
California (6)
AreaForestAcres
Cow CreekShasta-Trinity National Forest22,627
KellySix Rivers National Forest5,195
North Fork SmithSix Rivers National Forest37,898
Orleans Mtn. CSix Rivers National Forest15,589
Weaver BallyShasta-Trinity National Forest829
West YubaTahoe National Forest16,059
Oregon (13)
AreaForestAcres
Bull Of The WoodsMt. Hood National Forest8,843
Drift CreekSiuslaw National Forest6,333
Maiden PeakDeschutes National Forest26,432
Maiden PeakWillamette National Forest9,627
Mclennon MountainWillamette National Forest8,085
Mt. Hood AdditionsMt. Hood National Forest13,061
Salmon - HuckleberryMt. Hood National Forest17,570
TahkenitchSiuslaw National Forest5,799
W. BoundaryWinema National Forest2,345
Waldo - FujiWillamette National Forest15,273
Waldo - LakeWillamette National Forest2,993
Waldo - Salmon CreekWillamette National Forest3,195
Wind CreekMt. Hood National Forest5,438
Washington (2)
AreaForestAcres
BackboneGifford Pinchot National Forest1,201
Red MountainGifford Pinchot National Forest2,992
References (14)
  1. Bazzicalupo, A., S.C. Gonçalves, R. Hébert, S. Jakob, A. Justo, G. Kernaghan, R. Lebeuf, B. Malloch, R.G. Thorn, and A.K. Walker. 2022. Macrofungal conservation in Canada and target species for assessment: a starting point. FACETS 7: 448–463. doi:10.1139/facets-2021-0180 Online. Available: https://www.facetsjournal.com/doi/pdf/10.1139/facets-2021-0180 (Accessed 2022).
  2. Castellano, M.A., E. Cazares, B. Fondrick, and T. Dreisbach. 2003. Handbook to additional fungal species of Special Concern in the Northwest Forest Plan. Gen. Tech. Rep. PNW-GTR-572. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 144 pp. Online. Available: https://www.fs.usda.gov/pnw/pubs/pnw_gtr572.pdf
  3. Desjardin, D.E. 1998. ROD: Strategy 3 Collybia racemosa evaluation in unpubl. report on file at the Regional Mycology Lab, Corvallis, Oregon.
  4. Desjardin, D., M. Wood, and F. Stevens. 2014. California Mushrooms: The Comprehensive Identification Guide. Timber Press Inc., Portland, Oregon. 559 pp.
  5. Hughes, K.W., R.H. Petersen, J.E. Johnson, J. Moncalvo, R. Vilgalys, S.A. Redhead, T. Thomas, and L.L. McGhee. 2001. Infragenic phylogeny of Collybia s. str. based on sequences of ribosomal ITS and LSU regions. Mycological Research 105: 164-172.
  6. Index Fungorum and Species Fungorum. 2018. <i>In</i> Index Fungorum-Species Fungorum (<a href="https://indexfungorum.org" target="_blank">https://indexfungorum.org</a> and <a href="https://speciesfungorum.org" target="_blank">https://speciesfungorum.org</a>) database export on 16 June 2018. Royal Botanic Gardens, Kew.
  7. Index Fungorum and Species Fungorum. 2025. <i>In</i> Index Fungorum-Species Fungorum (<a href="https://indexfungorum.org" target="_blank">https://indexfungorum.org</a> and <a href="https://speciesfungorum.org" target="_blank">https://speciesfungorum.org</a>) database export on 29 September 2025. Royal Botanic Gardens, Kew.
  8. Index Fungorum. Online global fungal nomenclator. Index Fungorum Partnership (CABI, CBS, Landcare Research). www.indexfungorum.org (accessed 2014).
  9. ISMS-ONH. 2002. ISMS data; ONH protection extrapolations; GIS map for CORA16.
  10. Machnicki, N., L. L. Wright, A. Allen, C. P. Robertson, C. Meyer, J. M. Birkebak, and J. F. Ammirati. 2006. <i>Russula crassotunicata</i> identified as host for<i> Dendrocollybia racemosa</i>. North American Fungi [Online] 1.1 (2006): 1-7. DOI: http://dx.doi.org/10.2509/pnwf.2006.001.009 Online. Available: https://openjournals.wsu.edu/index.php/pnwfungi/article/view/1024 (Accessed 2022).
  11. MycoBank. 2025. MycoBank database download, export date January 2025. International Mycological Association. [http://www.mycobank.org]
  12. MyCoPortal. 2022. Mycology Collections Portal. Online. Available: https://www.mycoportal.org/portal/index.php. (Accessed 2022).
  13. Santa Cruz Mycoflora Project. 2022. The Santa Cruz Mycoflora Project. Online. Available: http://scmycoflora.org/ (Accessed 2022).
  14. Siegel, N., E.C. Vellinga, C. Schwarz, M.A. Castellano, and D. Ikeda. 2019. A Field Guide to the Rare Fungi of California’s National Forests. Bookmobile. Minneapolis, MN. 313 pp. Online. Available: https://www.mykoweb.com/CAF/PDF/Rare_Fungi_of_CA_National_Forests.pdf.